S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
Insufficient Links
When in the Insufficient Links state, the Start_LASR command should be executed to start the
LASR procedure to bring up additional links
The LASR procedure starts two timers; one for the Tx links and one for the Rx links.
When the LASR procedure is complete (all links become active or timeout), if sufficient links
are active, the group state machine transitions into the Operational State unless the Group is
blocked.
If sufficient links are not active after the LASR procedure completes, an interrupt is generated.
Since links will only transition into the Active state via a LASR procedure, PM can activate a
new LASR procedure with the same set of links and/or with additional links to bring up the
group.
Blocked and Operational States
While in the Blocked and Operational States, the link state machines are monitored to ensure
that sufficient links stay active. If insufficient links are detected active, the Group state machine
will transition into the insufficient links state and will stop accepting data from the ATM layer
for transmission.
LASR Procedure
Links will only become active as part of the LASR procedure. The add_group command will
automatically spawn a LASR procedure. To add links or recover links after group start-up, the
Start_LASR command should be used.
If an LASR procedure is in progress, additional Start_LASR commands will be rejected.
TX Links
When the LASR procedure starts, all Tx Links (participating in the LASR) in the unusable state
or Not_In_Group state will immediately transition into the Usable state if they are not faulted or
inhibited. (Note that the FE Rx Links may be reporting “Not in Group” at this point since their
LIDs have not been validated). Links in other states will remain in the same state. If test
patterns are to be transmitted on the links to test them prior to putting them in service, the Tx
links should be configured to be brought up with the inhibited state set. This keeps the Tx links
in the unusable state until they are released by a new LASR command (the PM_UNUSABLE
status can only be cleared by a LASR).
Once the Tx Links start to report the Usable state, a programmable timer is started. When either
the timer expires or all of the FE Rx links report the active state, the acceptable Tx Links will
transition to the Active state. This completes the LASR for the TX links.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
76
PMC [ PMC-SIERRA, INC ]
